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Protective Effects of N-Acetyl Cysteine against Diesel Exhaust Particles-Induced Intracellular ROS Generates Pro-Inflammatory Cytokines to Mediate the Vascular Permeability of Capillary-Like Endothelial Tubes.

Tseng CY, Chang JF, Wang JS, Chang YJ, Gordon MK, Chao MW - PLoS ONE (2015)

Bottom Line: Previous studies using in vitro endothelial tubes as a simplified model of capillaries have found that DEP-induced ROS increase vascular permeability with rearrangement or internalization of adherens junctional VE-cadherin away from the plasma membrane.Our data suggests that DEP-induced intracellular ROS and release of the pro-inflammatory cytokines TNF- α and IL-6, which would contribute to VEGF-A secretion and disrupt cell-cell borders and increase vasculature permeability.Addition of NAC suppresses DEP-induced ROS efficiently and reduces subsequent damages by increasing endogenous glutathione.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, College of Engineering, Chung Yuan Christian University, Zhongli district, Taoyuan city, Taiwan; Center of Nanotechnology, Chung Yuan Christian University, Zhongli district, Taoyuan city, Taiwan.

ABSTRACT
Exposure to diesel exhaust particles (DEP) is associated with pulmonary and cardiovascular diseases. Previous studies using in vitro endothelial tubes as a simplified model of capillaries have found that DEP-induced ROS increase vascular permeability with rearrangement or internalization of adherens junctional VE-cadherin away from the plasma membrane. This allows DEPs to penetrate into the cell and capillary lumen. In addition, pro-inflammatory cytokines are up-regulated and mediate vascular permeability in response to DEP. However, the mechanisms through which these DEP-induced pro-inflammatory cytokines increase vascular permeability remain unknown. Hence, we examined the ability of DEP to induce permeability of human umbilical vein endothelial cell tube cells to investigate these mechanisms. Furthermore, supplementation with NAC reduces ROS production following exposure to DEP. HUVEC tube cells contributed to a pro-inflammatory response to DEP-induced intracellular ROS generation. Endothelial oxidative stress induced the release of TNF-α and IL-6 from tube cells, subsequently stimulating the secretion of VEGF-A independent of HO-1. Our data suggests that DEP-induced intracellular ROS and release of the pro-inflammatory cytokines TNF- α and IL-6, which would contribute to VEGF-A secretion and disrupt cell-cell borders and increase vasculature permeability. Addition of NAC suppresses DEP-induced ROS efficiently and reduces subsequent damages by increasing endogenous glutathione.

No MeSH data available.


Related in: MedlinePlus

DEPs and the induced cytokines caused capillary VE-cadherin redistribution.Endothelial tube cells were treated for 24 h with DEPs±SnPP or TNF-α+IL-6± SnPP. An endothelial tube cell culture treated for 24 h with 100 ng/mL VEGFA was the positive control. VE-cadherin localization was then determined by epifluorescence imaging. White arrows indicate areas where VE-cadherin showed discontinuity around the cell membrane. Arrowheads indicate instances where VE-cadherin moved from the cell membrane to the interior and intracellular submembrane regions. Yellow arrows indicate cell-cell separations and globules of VE-cadherin that accumulated intracellularly near the cell membrane.
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pone.0131911.g006: DEPs and the induced cytokines caused capillary VE-cadherin redistribution.Endothelial tube cells were treated for 24 h with DEPs±SnPP or TNF-α+IL-6± SnPP. An endothelial tube cell culture treated for 24 h with 100 ng/mL VEGFA was the positive control. VE-cadherin localization was then determined by epifluorescence imaging. White arrows indicate areas where VE-cadherin showed discontinuity around the cell membrane. Arrowheads indicate instances where VE-cadherin moved from the cell membrane to the interior and intracellular submembrane regions. Yellow arrows indicate cell-cell separations and globules of VE-cadherin that accumulated intracellularly near the cell membrane.

Mentions: In contrast to VEGFA-dependent permeability, VE-cadherin-dependent cell-cell barriers are crucial to preventing the permeability of endothelial cells [8, 44–46]. The effects of TNF-α and IL-6 on VE-cadherin distribution in endothelial tube cells are shown in Fig 6. Discontinuity of VE-cadherin localization on the cell-cell border was observed (white arrows), and some VE-cadherin internalization was present, as indicated by punctate staining in the cytoplasm (triangular arrows). Some VE-cadherin was pulled from the cell surface into globules under the cell membrane (yellow arrows). To confirm whether TNF-α and IL-6 had the ability to rearrange the VE-cadherin pattern without HO-1 activation, cells were exposed to cytokines plus SnPP. Furthermore, to assess whether NAC restore the VE-cadherin redistribution, NAC was used with DEPs (10 or 100 μg/mL). VEGF-A was used as controls. Interestingly, endothelial tube structures were altered with increasing concentration of DEPs. At 100 μg/mL, cells were rounded up, and pulling and thinning of the cytoplasm between the cells were observed. Additionally, redistribution of the globules of submembrane VE-cadherin was found, while little discontinuity of VE-cadherin was observed at 10 μg/mL. Additionally, most of the cells exhibited regular separations from each other, and cells exposed to TNF-α and IL-6 along with the HO-1 inhibitor SnPP exhibited strong distribution of VE-cadherin on the cell border, indicating reduced permeability. These data suggested that TNF-α+IL-6 may contribute to the permeability of cell junctions, similar to VEGF-A exposure.


Protective Effects of N-Acetyl Cysteine against Diesel Exhaust Particles-Induced Intracellular ROS Generates Pro-Inflammatory Cytokines to Mediate the Vascular Permeability of Capillary-Like Endothelial Tubes.

Tseng CY, Chang JF, Wang JS, Chang YJ, Gordon MK, Chao MW - PLoS ONE (2015)

DEPs and the induced cytokines caused capillary VE-cadherin redistribution.Endothelial tube cells were treated for 24 h with DEPs±SnPP or TNF-α+IL-6± SnPP. An endothelial tube cell culture treated for 24 h with 100 ng/mL VEGFA was the positive control. VE-cadherin localization was then determined by epifluorescence imaging. White arrows indicate areas where VE-cadherin showed discontinuity around the cell membrane. Arrowheads indicate instances where VE-cadherin moved from the cell membrane to the interior and intracellular submembrane regions. Yellow arrows indicate cell-cell separations and globules of VE-cadherin that accumulated intracellularly near the cell membrane.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4492618&req=5

pone.0131911.g006: DEPs and the induced cytokines caused capillary VE-cadherin redistribution.Endothelial tube cells were treated for 24 h with DEPs±SnPP or TNF-α+IL-6± SnPP. An endothelial tube cell culture treated for 24 h with 100 ng/mL VEGFA was the positive control. VE-cadherin localization was then determined by epifluorescence imaging. White arrows indicate areas where VE-cadherin showed discontinuity around the cell membrane. Arrowheads indicate instances where VE-cadherin moved from the cell membrane to the interior and intracellular submembrane regions. Yellow arrows indicate cell-cell separations and globules of VE-cadherin that accumulated intracellularly near the cell membrane.
Mentions: In contrast to VEGFA-dependent permeability, VE-cadherin-dependent cell-cell barriers are crucial to preventing the permeability of endothelial cells [8, 44–46]. The effects of TNF-α and IL-6 on VE-cadherin distribution in endothelial tube cells are shown in Fig 6. Discontinuity of VE-cadherin localization on the cell-cell border was observed (white arrows), and some VE-cadherin internalization was present, as indicated by punctate staining in the cytoplasm (triangular arrows). Some VE-cadherin was pulled from the cell surface into globules under the cell membrane (yellow arrows). To confirm whether TNF-α and IL-6 had the ability to rearrange the VE-cadherin pattern without HO-1 activation, cells were exposed to cytokines plus SnPP. Furthermore, to assess whether NAC restore the VE-cadherin redistribution, NAC was used with DEPs (10 or 100 μg/mL). VEGF-A was used as controls. Interestingly, endothelial tube structures were altered with increasing concentration of DEPs. At 100 μg/mL, cells were rounded up, and pulling and thinning of the cytoplasm between the cells were observed. Additionally, redistribution of the globules of submembrane VE-cadherin was found, while little discontinuity of VE-cadherin was observed at 10 μg/mL. Additionally, most of the cells exhibited regular separations from each other, and cells exposed to TNF-α and IL-6 along with the HO-1 inhibitor SnPP exhibited strong distribution of VE-cadherin on the cell border, indicating reduced permeability. These data suggested that TNF-α+IL-6 may contribute to the permeability of cell junctions, similar to VEGF-A exposure.

Bottom Line: Previous studies using in vitro endothelial tubes as a simplified model of capillaries have found that DEP-induced ROS increase vascular permeability with rearrangement or internalization of adherens junctional VE-cadherin away from the plasma membrane.Our data suggests that DEP-induced intracellular ROS and release of the pro-inflammatory cytokines TNF- α and IL-6, which would contribute to VEGF-A secretion and disrupt cell-cell borders and increase vasculature permeability.Addition of NAC suppresses DEP-induced ROS efficiently and reduces subsequent damages by increasing endogenous glutathione.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, College of Engineering, Chung Yuan Christian University, Zhongli district, Taoyuan city, Taiwan; Center of Nanotechnology, Chung Yuan Christian University, Zhongli district, Taoyuan city, Taiwan.

ABSTRACT
Exposure to diesel exhaust particles (DEP) is associated with pulmonary and cardiovascular diseases. Previous studies using in vitro endothelial tubes as a simplified model of capillaries have found that DEP-induced ROS increase vascular permeability with rearrangement or internalization of adherens junctional VE-cadherin away from the plasma membrane. This allows DEPs to penetrate into the cell and capillary lumen. In addition, pro-inflammatory cytokines are up-regulated and mediate vascular permeability in response to DEP. However, the mechanisms through which these DEP-induced pro-inflammatory cytokines increase vascular permeability remain unknown. Hence, we examined the ability of DEP to induce permeability of human umbilical vein endothelial cell tube cells to investigate these mechanisms. Furthermore, supplementation with NAC reduces ROS production following exposure to DEP. HUVEC tube cells contributed to a pro-inflammatory response to DEP-induced intracellular ROS generation. Endothelial oxidative stress induced the release of TNF-α and IL-6 from tube cells, subsequently stimulating the secretion of VEGF-A independent of HO-1. Our data suggests that DEP-induced intracellular ROS and release of the pro-inflammatory cytokines TNF- α and IL-6, which would contribute to VEGF-A secretion and disrupt cell-cell borders and increase vasculature permeability. Addition of NAC suppresses DEP-induced ROS efficiently and reduces subsequent damages by increasing endogenous glutathione.

No MeSH data available.


Related in: MedlinePlus